Thee present invention relates to an improved process and article of manufacture for improved batch processing of tires during pyrolysis.
Disposal of the increasingly large number of tires used each year has become a critical problem in the waste disposal field today. If the organic constituents of a tire can be released in a cost effective manner through pyrolysis, the number of tires which have been stored in landfills and the like could be a viable source of energy and raw by-products. While many pyrolysis processes have been tried in various forms, there remains a need today for improved processes which would be cost effective such that tires can be decomposed by pyrolysis and the by-products sold for a profit.
There are generally two types of destructive distillation or pyrolysis procedures used today for pyrolyzing of waste materials. The first type of process is a continuous type process which is utilized to continually move pyrolysis material through a pyrolysis oven. This process utilizes a "cork screw" the arrangement or the like for moving the materials through the oven which provides for progressive decomposition of the shredded tire parts. The second the of process is a batch type process where a single material is placed in an oven and pyrolized until the material is completely broken down into its component pyrolysis products. In the past, both of these processes have relied on reducing the initial size of tires. Thus, shredding or otherwise grinding the tire material into smaller pieces was required for best results.
As will be readily realized to those skilled in the art, the shredding of tires is an extremely energy intensive type step which greatly reduces the cost effectiveness of the pyrolysis process. Such a step is required in the continuous type processes, because it is necessary to have proper size particles to run through the "cork screw" feeder. Even in the batch type processes reduction of feed stock size is normally necessary in that the smaller sized material allows for larger surface area of the feed stock and allows penetration of the heat at a more rapid rate thereby increasing the effectiveness of the pyrolysis process. There have been attempts to use a batch type process with a larger square bale or the like. However, these attempts were found ineffective in that the heat did not penetrate the center of the large cubical bails and therefore was found to be inefficient. Also, while the continuous process seems to be efficient in time used during processing of the material, because the pyrolysis bed is continually agitated a high percentage of the char materials go into the vapor stream thereby polluting the resulting useful by-products with desireable char. This method also results in a net reduction of available char which can be recycled or turned into valuable byproducts such as set forth in U.S. Pat. No. 5,037,628, Issue Date Aug. 6, 1991, entitled "Method For Reclaiming Carbonaceous Material From A Waste Material".
Thus, it is a goal in the present invention to provide an energy efficient method of processing of tires which will allow batch pyrolysis of tires, on a cost effective basis, resulting in improved char recovery and purer useable by-products.